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Anne Weiss recently repointed me to an interview with the epidemiologist Tom Jefferson about swine flu. Jefferson, let me stress, is a good epidemiologist. In the interview he makes a point I make on this blog, that research is heavily shaped by two questions: 1. what will make money? 2. what will be good for my career? (How curious that economists — with the exception of Veblen and Robin Hanson — spend so much more time on #1 than #2.) For example:

Interviewer Why aren’t researchers interested in [other viruses]?

Jefferson: It’s easy: They can’t make money with [them]. With rhinoviruses, RSV and the majority of the other viruses, it’s hard to make a lot of money or a career out of it. Against influenza, though, there are vaccines, and there are drugs you can sell. And that’s where the big money from the pharmaceuticals industry is. It makes sure that research on influenza is published in the good journals. And that’s why you have more attention being paid there, and the entire research field becomes interesting for ambitious scientists.

Because Jefferson is willing to tell the truth about virology, it is interesting what he doesn’t say.

The big glaring gap is that in a discussion about how to avoid getting sick he says nothing about improving immune function. Not one word. He isn’t a doctor. He doesn’t work for a drug company. There is no obvious reason he fails to discuss this. He is reflecting the blindness of his whole field, I believe. It isn’t a mystery how to improve immune function: Sleep better and eat more fermented food. I have blogged before (here, here, and here, for example) about how widely this supremely important question — how to improve immune function — is ignored.

The other gap in the interview is more subtle. Jefferson recommends hand-washing as a great way to avoid getting sick. He says:

I wash my hands very often — and it’s not all because of swine flu. That’s probably the most effective precaution there is against all respiratory viruses, and the majority of gastrointestinal viruses and germs as well.

Later he says:

One study done in Pakistan has shown that hand washing can even save children’s lives. Someone should get a Nobel Prize for that!

This theory of mine, which is supported by several lines of evidence, suggests that hand washing has a serious downside: It interferes with the self-vaccination system. Jefferson says nothing about any downside of hand washing. I’m not saying that Jefferson should have known of this theory of mine, of course not. (For one thing, the interview was before I thought of it.) My point is that — for reasons having nothing to do with money or career — he is too certain about what he knows. Maybe hand washing is only helpful when persons have weak immune systems or in places with large amounts of germs, such as hospitals. With strong immune systems in normal places, maybe it does more harm than good.

I became aware of the big gap in research after I improved my sleep and stopped getting colds. Before that, I had gotten the usual number of colds. No one had said that could happen — had said there was so much room for improvement in immune function. Anne Weiss became aware of the gap in research when she visited her doctor:

[More than 10] years ago I was seeing a family medicine doc who also taught epidemiology at [Famous Canadian University]. At one of my appointments I asked her how I could strengthen my immune system. She laughed in my face and told me that just was not possible.

Weiss says she was treated “as if I had asked about the existence of fairies or unicorns.” (She added that attitudes seem to be changing and one Canadian hospital now uses probiotics to prevent and treat C. difficile infection.)

Epidemiologists could easily study environmental control of immune function. They could ask questions like how many colds do you get in a typical year?, when you get a cold, how long does it usually take before the symptoms disappear? and during the last year, how many days did your longest cold last? As far as I know, they haven’t done so.

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12 Responses to “The Fallibility of Epidemiologists: Neglect of the Immune System”

I honestly wouldn’t be able to answer those questions very well without actually recording my colds for a year. I can say that I seem to get fewer/shorter colds in the last few years than I used to (I spent winters during my teens with a chronic respiratory infection) – maybe I’m doing better due to having children? I don’t know, but sometimes I’m surprised to find myself without cold symptoms.

The hand-washing studies came out of what doctors should do. They are significantly more exposed than anybody else since they see sick people all day. Back in the real world, SR should mark this as “medical error.”

I am wonder in psychology practices, what percent of complaints are sub-clincal? 85? 95? 99%

Well, the other thing to take into account is potency of the disease vector. Obviously most of the time we are exposed to a cold, we don’t get sick, so immune function plays a huge role there. However for a lot of the things that go via the fecal-oral route, I think there are much higher rates of infection, hence less variance due to the immune system. For example, with food poisoning, my anecdotal experience is that if you eat the thing that is poisoned, you will get sick, with several instances of shared sickness across multiple people. Similarly with things like cholera, salmonella, etc.

But I could be wrong and immune function could have a big role there. Anyway, the potency of the fecal-oral route is I’m pretty sure the main reason for hand washing. Best practice in normal life is probably wash your hands after using the bathroom, but not that often otherwise, which is I suspect what most people do.

Although one counter-example I just thought of is eating street food in a new developing country. Usually after the first illness or two the body adjusts, although when I lived in Egypt I knew several people that never did and just couldn’t eat street food, so maybe they had weaker immune function?

Rashad: I suspect that in most cases food poisoning is actually more about toxins than microbes – ie, it’s the nasty chemicals the bacteria made before you ate them, not the bacteria themselves. It’s also the case what we think of as food poisoning symptoms are actually immune responses, and if we want to measure immune system strength we should be looking at who’s sick two days later. I also suspect that when people go to developing countries, their immune systems start having false positives: they fire in response to things that are actually harmless.

I whole heartily agree with much of what you have said here but I have to pick up on the evolutionary point that we haven’t been prepared to live in cities of 1 million+.

I think you might get better results from asking people how many days they missed work last year to illness. I get colds but I shrug them off so fast and they are so mild that I haven’t missed a day of work to illness in 5 years.

Seth: I agree, missed days of work is a good question. And you make a good point about cities of 1 million. In the past ten years I think all of my colds appear to have come from the combination of (a) poor sleep and (b) riding crowded public transit.

Quite a few travelers who normally are relatively free of colds develop bad colds or the flu following a long flight in economy class. Business class is considered less risky by those who travel frequently for that reason.

Some mentioned they hadn’t counted their colds. I have. For the first 58 years of my life, I had one every 4-6 weeks. Then I found I had coeliac disease and stopped eating gluten. Also, my nutritionist put me onto high levels of probiotics for 3 months, and then a maintenance dose, which I take to this day. In the last 7 years, I have had only 4 illnesses! I attribute this to both the lack of gluten (no gut damage) and the probiotics.

Fermented foods are a very effective way of getting probiotics, when you can work out how to make them/get them. These days I have Kefir, and want to experiment with others.